In V 1.2.0, if the reference was "a", and GTC said "A", this wouldn't be a problem. However, in V1.2.1, this is no longer the case and causes problems like
10 779284 GSA-rs2486591 g A,G . PASS
V1.2.0 would have been:
10 779284 GSA-rs2486591 G A . PASS